How did the Trans-Atlantic slave trade affect relations between the kingdoms of Africa?

Most of the effects by the Slave Trade where really bad.

Here are some of the effects that I know:

1. A lot of war erupted from the kingdoms of Africa, since a lot of them wanted to kidnap others and sell them to Europeans.

2. Kingdoms of Africa had a lot of decreased population.

3. The kingdoms had a decrease in economy, since most of the low and working class were just sold out.